In order to improve fuel consumption of industrial vehicles, there has been known a hybrid industrial vehicle whose power is supplied from a motor generator in addition to an engine. Generally, the hybrid industrial vehicle can store regeneration energy of a generator motor in a battery, and can reuse it at the time of powering.
In such hybrid industrial vehicle, extreme decrease and increase of a charging rate of a battery reduce a battery life, and thus it is known to appropriately manage the charging rate of the battery (for example, refer to PTL 1).
For example, in PTL 1, a technique has been disclosed that detects a charging rate and a battery temperature, and controls discharge allowable electric power in order to protect a battery in a hybrid industrial vehicle.
Specifically, PTL 1 discloses to use a smaller set value of the discharge allowable electric power from the battery when the battery temperature is low as well as when it is high, or the charging rate is small.